code: def test_predicate_null_block_asof_join() -> None:
      left = (
          pl.DataFrame(
              {
                  "id": [1, 2, 3, 4],
                  "timestamp": [
                      datetime(2022, 1, 1, 10, 0),
                      datetime(2022, 1, 1, 10, 1),
                      datetime(2022, 1, 1, 10, 2),
                      datetime(2022, 1, 1, 10, 3),
                  ],
              }
          )
          .lazy()
          .set_sorted("timestamp")
      )
  
      right = (
          pl.DataFrame(
              {
                  "id": [1, 2, 3] * 2,
                  "timestamp": [
                      datetime(2022, 1, 1, 9, 59, 50),
                      datetime(2022, 1, 1, 10, 0, 50),
                      datetime(2022, 1, 1, 10, 1, 50),
                      datetime(2022, 1, 1, 8, 0, 0),
                      datetime(2022, 1, 1, 8, 0, 0),
                      datetime(2022, 1, 1, 8, 0, 0),
                  ],
                  "value": ["a", "b", "c"] * 2,
              }
          )
          .lazy()
          .set_sorted("timestamp")
      )
  
      assert left.join_asof(right, by="id", on="timestamp").filter(
          pl.col("value").is_not_null()
      ).collect().to_dict(as_series=False) == {
          "id": [1, 2, 3],
          "timestamp": [
              datetime(2022, 1, 1, 10, 0),
              datetime(2022, 1, 1, 10, 1),
              datetime(2022, 1, 1, 10, 2),
          ],
          "value": ["a", "b", "c"],
      }
  
imports: from datetime import date, datetime, timedelta
  from typing import Any
  import numpy
  import pytest
  import polars
  from polars.testing import assert_frame_equal
  from polars.testing.asserts.series import assert_series_equal
label_desc: Use image node_id 2 for calling a global function with example usage: test_predicate_null_block_asof_join() without return types